Racial disparities in cancer treatment disproportionately affect Black patients with cancer. The 2003 Institute of Medicine report, Unequal Treatment, and research from communication science, social psychology, and clinical medicine suggest two factors that likely contribute to these treatment disparities: 1) the quality f patient-physician communication during racially discordant (i.e., Black patient, non-Black physician) clinic visits in which treatment is discussed, and 2) patient and physician pre-visit racial attitudes. With regard to communication, prior research, including our own, demonstrates that racially discordant clinic visits are less positive and productive than racially concordant clinic visits, and a great majority (75%) of visits with Black patients are racially discordant. Research also suggests that patient and physician racial attitudes, specifically patient group-based mistrust in medical care and physician implicit bias against Black people, affect the quality of communication during clinic visits. Racial attitudes are largely expressed through subtle nonverbal/paraverbal communicative behaviors; however, little research has identified the behavioral manifestation of racial attitudes during clinic visits. A greater understanding of te influence of racial attitudes on patient and physician nonverbal/paraverbal communication is needed because they convey more meaning and emotion in interactions, compared to verbal behavior. We propose to address this gap through a secondary analysis of data from a larger study of clinical communication and Black-White cancer treatment disparities. Data to be used include: video recorded cancer clinic visits between Black patients (n=120) and non-Black oncologists (n=19), transcripts of the clinic visits, patient and oncologist self-reported pre-visi racial attitudes and post-visit perceptions of the clinic visit and of each other, and medical recod data on treatment received. Our first aim is to identify the manifestations of patient and physician negative racial attitudes by applying an investigator developed, theory-based nonverbal/paraverbal communication coding system to thin slices of the data set of video recorded clinic visits. Our second aim is to use findings from Aim 1 to determine a) whether and how physician and patient racial attitudes influence nonverbal/paraverbal communication behaviors, and b) the extent to which those behaviors influence patient and physician perceptions of each other and the appropriateness of treatment (consistent with NCCN guidelines). Our study is significant because findings will deepen our understanding of relationships among racial attitudes, clinical communication, and treatment disparities, and inform interventions to improve communication and reduce healthcare disparities. This research is innovative because it focuses on nonverbal/paraverbal communication in racially discordant clinic visits, it employs a dyadic theory that considers interpersonal communication from an intergroup level, it utilizes thin slice methodology in a novel way, and it employs multi-level statistical analyses that will result in a unique understanding of the reciprocal nature of the cliic visit.